Examples of prior art related to a bed equipped with side rails include Japanese Domestic Republication No. 2003-527204 (patent document 1), Japanese Patent No. 2998841 (patent document 2), and Japanese Patent No. 2595474 (patent document 3).
A bed side-rail is disclosed in patent document 1, as shown, e.g., in FIGS. 1 and 2 of same patent document, wherein a back side-rail is raised along a deck that supports the back bottom, or the leg side-rail is moved in the direction separated from the back side-rail and along the longitudinal direction of the bed frame in conjunction with the back bottom raising action, with the object being to substantially stabilize the gap between the back side-rail and leg side-rail when the back bottom is raised.
In addition, a bed equipped with side rails is disclosed in patent document 2, as described in FIG. 1 and paragraph 0007 of same patent document, wherein a fence part 15a of a side fence 15 on a side of a back bottom 12a and a fence part 17b of an inserting-type side fence 17 on a side of a leg bottom 12d are provided so as to be separated in the width direction of the bottom, whereby the side rails are kept from producing an interference even if the side fence 15 on the side of the back bottom 12a follows the back bottom 12a, and the fence part 15a is brought to a position overlapping the fence part 17b of the inserting-type side fence 17 when the back and knees of the bottom 12 are raised.
Furthermore, a bed equipped with side rails is disclosed in Patent Document 3, as shown in FIG. 3 of same patent document, wherein a side rail on the side of the back bottom is upwardly movable in conjunction with the back bottom raising action, and the leg bottom side-rail is secured in place.
Patent document 1: Japanese Domestic Republication No. 2003-527204
Patent document 2: Japanese Patent No. 2998841
Patent document 3: Japanese Patent No. 2595474